Advanced Photodiode Detector For Medical CT Imaging: Design and Performance

This paper presents an advanced photodiode detector design for medical imaging applications, especially computerized tomography. The detector is silicon based and integrates the through-wafer interconnection technology into conventional front illuminated photodiode. The number of photodiode elements in the detector can be extended in 2D without reducing the photodiode active area. The signal of each photodiode element can be directly read out from the backside of the detector. Moreover, detectors can be tiled together in 2D without any physical limitation. A test photodiode detector was designed and demonstrated with 3 x 3 photodiode matrix arrangement in this paper. Different parameters were measured and analyzed from the demonstrated chip and test structures. The results show that the detector inherits most of the performance advantages from the conventional front illuminated photodiode, and all the parameters can either meet or exceed the requirements of modern CT systems.